There seems to be a happy concurrence of causes in human affairs, which checks the growth of trade and riches, and hinders them from being confined entirely to one people; as might naturally at first be dreaded from the advantages of an established commerce. Where one nation has gotten the start of another in trade, it is very difficult for the latter to regain the ground it has lost; because of the superior industry and skill of the former, and the greater stocks, of which the merchants are possessed, and which enable them to trade on so much smaller profits. But these advantages are compensated in some measure, by the low price of labor in every nation which has not an extensive commerce, and does not much abound in gold and silver. Manufactures therefore gradually shift their places, leaving those countries and provinces which they have already enriched, and flying to others, whither they are allured by the cheapness of provisions and labor, till they have enriched those also, and are again banished by the same cause.